1. Field of the Invention
The present invention relates to a TV broadcast receiver.
2. Description of the Related Art
In recent years, a majority of tuners used in TV broadcast receivers are frequency synthesizer-type PLL tuners, and generally any frequency inputted from a microcomputer is made to syntonize the locally oscillated frequency at the predetermined frequency to receive the desired channel. For tuning in a station with this PLL tuner, a broadcast signal is searched automatically in advance based on a channel plan for each country (for each region).
If the channel plan is a standard one, the standard step wherein the frequency between the respective channels in the VHF band and the UHF band is almost constant is adopted, and this standard step is a step of 7 MHz in the VHF band and a step of 8 MHz in the UHF band. Therefore, when the place of destination is known and the channel plan is also known, normally the product is preset in the factory before the shipment of the product.
However, there are cases where the number of countries involved is very large such as in Europe and the channel plan adopted is different from the standard channel plan due to the relationship with the neighboring countries. For example, in Europe CCIR (Comite Consultatif International Radiophonique) adopts the standard channel plan. However, in Italy, Ireland, Indonesia and Australia, VHF-Low is different from the standard, and frequency partially shifts by 1-2 MHz.
FIG. 3 shows the standard channel plan (list of frequency assignments) in Europe established by the CCIR (Comite Consultatif International Radiophonique), FIG. 4 shows the channel plan in Australia, and FIG. 5 shows the channel plan in Ireland. In FIG. 3, the lowest channel is the channel 2, and the image intermediate frequency 48.25 Mhz for the channel 2 is the minimum frequency, while in Australia as shown in FIG. 4 the minimum frequency is 46.25 MHz of the channel 0, in Ireland shown in FIG. 5 the minimum frequency is 45.75 MHz. of the channel A. Thus, this list of frequency assignments reveals that each country has adopted channel plans with different central frequencies and frequency steps. Therefore, the products shipped for these regions were required to store all the channel plan data corresponding to these plural destinations in their memory or to set the channel plan for each destination of shipment.
In view of such regional situation, Japanese Unexamined Patent Application Publication (JP-A) No. 1995-264008 disclosed a channel select unit capable of tuning in different channel plans simply by selecting channel even in a region where it is possible to tune in two or more channel plans by presetting a channel for each channel select position and a TV broadcast receiver provided with the same.
The art described above had the following problem. Specifically, in the case of having all the channel plans for each country stored in the memory as in the former case, an increase in cost is still unavoidable, and in the case of shipping the product by presetting different channel plans for each country, work productivity is reduced and therefore an increase in cost is unavoidable as in the latter case. Moreover, the art described in JP-A-1995-264008 is for presetting both of the airwaves in an area where there are a plurality of airwaves, and has a different problem from that of the present application.